P114

Shipping of juvenile porcine islets in silicon rubber membrane (SRM) vessels

Bradley P. Weegman¹, Efstathios S. Avgoustiniatos¹, Michael J. Taylor², Simona C. Baicu², Jennifer P. Kitzmann¹, Kate R. Mueller¹, William E. Scott III¹, A.N. Balamurugan¹, John R. Wilson³, Klearchos K. Papas¹

¹Surgery, University of Minnesota, Minneapolis, MN; ²Cell and Tissue Systems Inc., N. Charleston, SC; ³Manufacturing, Wilson Wolf, New Brighton, MN, United States

Introduction: Porcine islet transplantation (PITx) is emerging as a promising treatment option for patients with type 1 diabetes that can be potentially applied at the larger scale. The use of “medical grade pigs” is required for clinical application. Juvenile, as opposed to adult pigs are attractive as donors when considering the cost and logistics of raising them in specialized facilities. However isolation and culture of islets from juvenile pig pancreata is notoriously difficult. It is important to demonstrate that juvenile porcine islets can be successfully, isolated, cultured and shipped to distant facilities without substantial loss of tissue amount or viability. A method for shipping cultured juvenile porcine islets using gas-permeable silicon rubber membrane bottom (SRM) vessels in temperature controlled containers is investigated here.

Methods: Islets were obtained using standard protocol; briefly, pancreata were procured from living juvenile porcine donors and islets isolated using the Ricordi method. Islets were purified using Ficoll density gradients and cultured for 6-7 days in SRM vessels (Wilson Wolf Manufacturing Corp. New Brighton, MN). Islets were then packaged in phase change temperature controlled shipping boxes as described previously by our group and shipped overnight. Islets were quantified by DNA or assessed for viability by oxygen consumption rate normalized to DNA (OCR/DNA; values reported are Means ±SEM) both immediately prior to and post-shipment.

Results: OCR/DNA was on average slightly higher but not significantly different post-shipment (175±25 nmol/min/mg DNA; n=5) when compared to pre-shipment (159±16; n=5). DNA recovery post-shipment was 65±6% with n=4.

Conclusions: A slight increase in average viability and only a minor loss of viable tissue during shipment indicates that most of the viable tissue survived while primarily unhealthy tissue was lost. These results are promising considering the historic difficulty in the culture of juvenile islets. The temperature controlled shipment of juvenile porcine islets using SRM culture devices appears to be a preferred means of islet culture and distribution.